Easier Approach to Electronic Projects

Shadow Detector Alarm

This is also known as Sun up alarm, in this circuit you can set the LDR’s sensitivity by 100k potentiometer, you can set it with any lamp around your room (tube light, bulb, LED etc) by varrying the 100k potentiometer. We can also control the buzzer time by 1M potentiometer 😉

You can Enhance this project and set the sensitivity of the LDR with a lazer light and keep it on the way of any door circuit at one side and lazer at other side of the door and a then you can make this project to buzz as soon as some one enters in a room 😉

I personally set this project in my room with sensitivity of tube light and whenever i came in and turn my room’s tube light on

Parts Required:

  1. 555 Timer
  2. 100k & 1M potentiometers 
  3. 10k, 1Mx(3), 47k
  4. 0.1μF, 0.01μF & 10μF
  5. LDR
  6. BC337 transistor
  7. Beeper/Buzzer
  8. 9v Battery Supply

   Circuit Diagram:

Bread board Arrangement:     Strip Board Version:











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